Chain Law Requirement Begins Tomorrow

August 31, 2012 - Statewide Transportation Plan - DENVER – The Colorado Department of Transportation (CDOT) is reminding commercial vehicle drivers that beginning on Saturday, September 1, commercial vehicles weighing more than 26,000 pounds and traveling Interstate 70 between Dotsero (mile 133) and Morrison (mile 259) must carry sufficient chains along this segment until May 31, 2013.

“We’ve had instances when snow’s fallen in the high country in September so we want commercial vehicle drivers to be in compliance with the ‘must carry’ chain requirement and be prepared for winter-type road conditions, even at this early date,” said CDOT Region Transportation Director Tony DeVito.  “We have lots of chain stations as well as other programs to assist drivers during the winter months.”

Colorado’s chain law was enacted in 1996.  It applies to all interstate, federal and state highways.  It includes two levels for commercial vehicles:

    • Chain Law Level 1 requires all single drive axle combinations commercial vehicles to chain up.  All four drive wheels must be chained; cables are not permitted as an alternate traction device. All other commercial vehicles must have snow tires or chains. Level 1 may be implemented any time there is snow covering any part of the traveled portion of pavement on an ascending grade.
    • Chain Law Level 2 requires all commercial vehicles to chain up. Auto transports must comply to the extent possible without causing damage to hydraulic lines. Buses must chain two drive wheels to comply.  Level 2 may be implemented any time there is snow covering the entire traveled portion of pavement on an ascending grade or when driving conditions dictate this level is necessary to protect safety and minimize closures.

The alternate traction control device known as the AutoSock™ remains an approved device in Colorado.  Commercial vehicles (both single and double-axle) exceeding 26,000 Gross Vehicle Weight or vehicles carrying 16 passengers or more have the option of using AutoSock™ rather than chains.  This traction control device is a fabric that slips over a vehicle’s outer driving wheels, providing extra traction on snowy and icy roads.  It also can be installed over the tire in less time than traditional chains.

To safeguard truck drivers and others while they are chaining up or down, CDOT has constructed 21 lighted chain stations along the I-70 west corridor Ten stations are on westbound I-70 – at mileposts 263, 260, 254 (Buffalo Overlook), 228, 223, 221, 219, 213 (brake check area) and 197 (scenic area) and 179.  Eastbound I-70 has 11 stations – at mileposts 178, 183, 184 (shoulder), 187 (shoulder), 195, 203 (scenic area), 205, 219, 228, 241 and 251.

Chain stations also are located east of Denver on I-70 – eastbound near E-470 (mile 289) and Agate (mile 343) and westbound near Limon (mile 358) – and south of Denver on I-25 – northbound near Monument (mile 157) and southbound near Larkspur (mile 172).

CDOT is encouraging drivers to use the chain stations and follow the reduced speed limit, which will be displayed at electronic Variable Speed Limit signs near each station when the chain law is in effect.  Drivers also should be aware of the right lane restriction for all slow moving vehicles on uphill grades greater than six percent, except when it is necessary to obey traffic control devices, exit or enter the interstate or when weather or traffic conditions require otherwise.

The Quick Clearance program again will be providing standby heavy wreckers at strategic locations along I-70, between Floyd Hill and Vail Pass, allowing them to quickly move spun-out or stalled commercial vehicles from traffic lanes to a safe location.  CDOT begins the program during the Thanksgiving weekend.

Chain Assistance also is returning this season. Drivers will be able to purchase chains and chain-up services from approved vendors when they are present at any one of the 21 chain stations along I-70. It also is scheduled to begin operating over Thanksgiving.

E-mail and text message alerts are available to notify commercial drivers of road conditions and when the chain law is in effect.   Please visit and click on the green cell phone icon in the upper right-hand corner below the search function and select the appropriate items under Commercial Vehicles or other areas of traveler interest.

Road condition and chain law information also is accessible at or by calling 511.